<html>
	<head>
		<style type="text/css">
			.square-01,.square-02,.square-03,.square-04 {
				color: #000;
				text-align: center;
				line-height: 100px;
				float: left;
				margin-right: 10px;
				padding: 10px;
				width: 150px;           /*元素的宽度*/
				height: 100px;			/*元素的高度*/
				border: 2px dashed #333; /*元素的边框*/
				background: url('./cccat.jpg') no-repeat;
			}
			.square-01 {
				background-size: 50px;
			}
			.square-02 {
				background-size: 50%;
			}
			.square-03 {
				background-size: cover;
			}
			.square-04 {
				background-size: contain;
			}
		</style>
	</head>
	<body>
		<div class="square-01"></div>
		<div class="square-02"></div>
		<div class="square-03"></div>
		<div class="square-04"></div>
	</body>
</html>